US President Donald Trump wanted to have Syrian President Bashar al-Assad assassinated a year ago but his defense secretary ignored the request, according to a new book by famed Watergate reporter Bob Woodward. "This is the worst job I've ever had", Kelly is quoted as saying at a staff meeting.

He describes Trump regularly insulting key members of his own team, branding Attorney General Jeff Sessions "mentally retarded" and a "dumb Southerner", and former chief of staff Reince Priebus "like a little rat".

Trump's former lawyer John Dowd conducted a mock interview with Trump to convince him that he would commit perjury if he agreed to talk to Special Counsel Robert Mueller, who is leading the Russian Federation investigation, the book says.

Dowd issued a statement Tuesday claiming he had been misquoted by Woodward and challenging Woodward's account of a January 2018 mock interview of the president by his legal team meant to determine whether Trump could be trusted to testify before special counsel Robert Mueller. I think you've always been fair.

Trump specifically denied Cohn took papers from his desk, saying "there was nobody taking anything from me" and suggesting that, "It could be just made up by the author".

Woodward's latest book, Fear, is focused on the Trump White House and is set to be officially released on September 11.

The chemical attack, which was carried out by Assad, killed dozens and prompted a USA missile strike against a Syrian air base which Washingtonsaid was used to launch the strike.

Bob Woodward, who gained national fame for his reporting on the Watergate scandal in the 1970s, talked to top aides for the book with the understanding that he would not reveal how he got his information, the Post said. "He couldn't even be a one-person country lawyer down in Alabama".

"While responsible policy making in the real world is inherently messy, it is also essential that we challenge every assumption to find the best option", Mattis said. But Mattis reportedly told an aide: "We're not going to do any of that".

"I never spoke to him", Trump told The Daily Caller.

John quotedWaPo's summary of Woodward's book at great length in his post but there are so many jaw-dropping bits that no excerpt can do them justice.

"Let's [expletive] kill him".

Separately, Mattis denied on Tuesday that he had criticized the president in the way Woodward described. Woodward tells Trump he had contacted multiple officials to attempt to interview Trump and was rebuffed. Trump himself has complained that it will be a "bad book".

Woodward goes on in the excerpt to say that during a National Security Council meeting Jim Mattis got frustrated when Trump repeatedly asked him why the USA spends so much money on the Korean peninsula. Then, he told the President directly that the book is "a tough look at the world and your administration and you".

"John, I understand", Mueller replied, according to Woodward, but insisted, "I need the president's testimony".

Other aides insulted Trump behind his back. In some cases, senior aides would reportedly pluck official papers from Trump's desk before he could sign them.

The Washington Post on Tuesday released an audio recording of an 11-minute conversation between Trump and Woodward in early August, with Trump calling Woodward after finding out that the manuscript for Fear: Trump in the White House had been finished.